The present invention relates to prism sensors, and is particularly directed to a prism sensor and method of operating a prism sensor for a check processing module of a self-service check depositing terminal, such as a check depositing automated teller machine (ATM).
In a typical check depositing ATM, an ATM customer is allowed to deposit a check (without having to place the check in any deposit envelope) in a publicly accessible, unattended environment. To deposit a check, the ATM customer inserts a user identification card through a user card slot at the ATM, enters the amount of the check being deposited, and inserts the check to be deposited through a check slot of a check acceptor. A check transport mechanism receives the inserted check and transports the check in a forward direction along a check transport path to a number of locations within the ATM to process the check.
If the check is not accepted for deposit, the check transport mechanism transports the check in a reverse direction along the check transport path to return the check to the ATM customer via the check slot. If the check is accepted for deposit, the amount of the check is deposited into the ATM customer's account and the check is transported to a storage bin within the ATM. An endorser printer prints an endorsement onto the check as the check is being transported to and stored in the storage bin. Checks in the storage bin within the ATM are periodically picked up and physically transported via courier to a back office facility of a financial institution for further processing.
In some known check depositing ATMs, certain components are housed in modular units which, in turn, are housed in a larger module. The larger module is sometimes referred to as a “check processing module” (CPM). Such modules are included in ATMs provided by NCR Corporation, located in Dayton, Ohio. One example is Model No. CPM2 in which a modular unit called a “pocket module” is located in approximately the central portion of the CPM. Another example is Model No. CPM3 in which the pocket module is located in approximately the bottom portion of the CPM. Still another example is Model No. CPM4 in which the pocket module is located in approximately the top portion of the CPM.
Also, in some known check depositing ATMs, prism sensors are used to detect presence of a check in the check transport path. A typical prism sensor includes a prism-shaped light reflector disposed on one side of the check transport path, and a light emitter and a light receiver which are located on the opposite side of the check transport path. Light from the emitter is directed across the check transport path to the reflector. The light is then reflected off of the reflector and directed back across the check transport path to the receiver.
The prism-shaped light reflector is usually molded from an optically clear acrylic material. The acrylic material needs to be quite thick to account for misalignment tolerances, and to fully enclose the light path. However, as is known, the molding of thick acrylic material is quite difficult to achieve without sink. Any sink on reflective surfaces of the reflector results in drastic reduction of the intensity of reflected light. As such, acrylic prism sensors are quite expensive because of the long cycle times required to manufacture parts which are relatively free of sink. Moreover, since parts of known acrylic prism sensor are glued into place, great care needs to exercised to avoid getting glue on the reflective surfaces of the sensor. Any glue on the reflective surfaces would also drastically reduce the intensity of reflected light. It would be desirable to provide a prism-type of sensor which is relatively low cost, relatively easy to assemble, and relatively easy to disassemble whenever disassembly is required.